One of the most controversial (and obscure) aspects of lore is S-Cells, the unique feature in Saiyan's bodies that allows them to transform into . A great quantity of inherited S-Cells is the reason why is so powerful, but this explanation, provided by Akira Toriyama himself, is still one of the most hated retcons in the history of .
The original Super Saiyan transformation happened during . After the villain murdered his best friend Krillin in front of his eyes, Goku experienced the source of rage needed to trigger the transformation into Super Saiyan, a legendary form whose existence was transmitted through myths and stories by the inhabitants of Planet Vegeta.
Many years later, when the sequel was in full swing, series creator that seemingly fixed all previous misconceptions about the Super Saiyan transformation.
Toriyama provided this explanation to support the appearance of , who were easily able to transform into Super Saiyans because, in their universe, their species is actually peaceful. However, many fans of were unhappy with this retcon, because they felt that it diminished Goku's tragic awakening on Planet Namek, making Krillin's death almost meaningless. However, it should be remembered that Toriyama immediately gave up on his earliest explanation for Goku's transformation, first by having Vegeta become a Super Saiyan without a 'pure heart', and then with
Some fans also pointed out that the S-Cells theory bears a striking resemblance with the Midi-chlorians, another very famous retcon, from the Star Wars franchise, that is not very appreciated by fans. It is indeed a bit disappointing to have come from a genetic trait rather than from a tragic experience and awakening. However, Toriyama made sure to add that a gentle spirit alone is not enough to increase the number of S-Cells, one also needs the battle power that comes from continuous fighting and training. So, while the S-Cells retcon remains one of the most controversial in history, this should not be considered the only reason for Goku's unique strength.